The two defining lesions in Alzheimer disease (AD) brains are senile plaques and neurofibrillary tangles with beta-amyloid (Abeta) and tau proteins as the main components, respectively. The major components of the amyloid deposits in AD are the 40 and 42-amino acid long ß-amyloid peptides [Aß (1-40) and Aß (1-42)]. At lower concentrations, ß amyloid peptides are found as a normal constituent of biological fluids including CSF and plasma. In the last decade, several studies have reported increased levels of tau and decreased concentrations of Aß (1-42) in CSF from AD patients.
Since CSF is not always available, the use of plasma has also been investigated. However, the true value of measurement of Aß peptides in plasma is not yet completely clear. Especially tau and phospho-tau measurements in plasma are difficult, since the concentrations are very low. In addition, also of Aß(1-40) to Aß(1-42) ratios can be measured.
ApoE is a protein which, in the blood, helps carry cholesterol and fat. The three common forms of the gene for this protein are Apoε2, Apoε3, and Apoε4. Apoε4 has been identified as a genetic risk factor for Alzheimer's disease.
Assays (Innogenetics, Ghent, Belgium)
- INNOTEST® hTAU Ag [ELISA]
- INNOTEST® PHOSPHO TAU (181P) [ELISA]
- INNOTEST® β-AMYLOID (1-42) [ELISA]
- Multiparameter INNO-IA AlzBio 3; A multi-analyte bead-based immunoassay for the simultaneous quantification of human Aß1-42, total tau, and P-tau181P in CSF [LUMINEX xMAP®]
- Multiparameter INNO-BIA plasma Aß forms A multi-analyte bead-based immunoassay for the simultaneous quantification of human ß-amyloid (Aß) forms Aß1-42 , Aß1-40 , AßN-42 , and AßN-40 in plasma. [LUMINEX xMAP®]
- The ELISA measures each analyte separately in a solid phase of the microtiter plate, whereas the Luminex xMAP® is as multiparamater assay, based on simultaneous measurement of the analytes in a suspension of beads.
ApoE testing
- Using the INNO-LiPA ApoE test, based on PCR on human DNA
Samples
- Cerebrospinal fluid, collected and stored in polypropylene tubes (-70ºC)
- Plasma, collected and stored in polypropylene tubes (-70ºC)
